I've had my H-K unit fixed by Iron Cross Audio. They did a lot of work with it. Totally new faceplate, fixing the water issue, mainboard and a whole new main chassis because of a stripped mounting screw. They have a fast "turnaround" service. Mine was done in a day then shippad back. I got 6 months warranty + 3 months of free "winter warranty".
All of this costs me $ 250 flat fee + $40 for the new main chassis.
My H-K unit is better then new.....
Great people to deal with...